‘Happy-clappy” is Tracyanne Campbell’s offhanded description of the kind of music her band is famous for. That sounds about right. For more than a decade, Camera Obscura, the Scottish indie-pop band she fronts as its lead singer and songwriter, has made the musical equivalent of fluorescent piñatas, one just whack away from a sugar rush.

Perhaps that’s why “Desire Lines,” the band’s new and fifth album since its 2001 debut, comes off as such a pleasant surprise. Rather than filling every inch of space, the songs simply breathe.

“I think that’s one of the main things we wanted to achieve. Our previous albums are quite jampacked with singing and dancing and throwing the kitchen sink at it,” Campbell says. “At the time we made records we were pleased with, but we just needed a bit of space and wanted to make a record that reflected that. Something that was more sophisticated and mature in the sense that we could show people that we don’t just make a big wall of sound.”

That’s a tricky proposition for a group so adept at making heartbreakers sound like party anthems. Stripped of their lyrics, some of Camera Obscura’s best-known songs — “Lloyd, I’m Ready to be Heartbroken,” “French Navy” — are staggeringly sad. Campbell, who brings Camera Obscura to the Bank of America Pavilion on Wednesday, opening for She & Him, is mindful of the expectations her band has engendered over the years.

CAMERA OBSCURA

“Coming to make this record, I was focused on what I didn’t want,” she says. “We didn’t want it to sound full, with every single bit of space filled up with something. Those wall-of-sound albums we made were great, but I didn’t have the patience or energy to deal with that. We wanted some clarity, and we were keen to let Tucker, the producer, know that.”

That would be Tucker Martine, the Grammy-nominated producer whose credits include My Morning Jacket and the Decemberists. Already a fan of Camera Obscura’s aesthetic, he was charged with helping the group to amplify its palette.

“I think this album captures the distinct personality of the band members maybe more than the previous albums,” Martine says. “That was something that was important to them at this point in their career.”

“Of course the challenge for me was that I loved what they had done before, so now if someone doesn’t like this new album, I get blamed for it,” he adds, jokingly.

“Quite often we’d have a bit of a struggle,” Campbell admits. “He’d be like, ‘Let’s do this,’ and we’d say, ‘No, it’s too much like the other records.’ There’s only so much you can deny about what you do. Songs like ‘Do It Again’ are quite similar to something that would be on previous records, and I was less keen on that kind of thing. At the same time there was nothing else we could do with that song but make it a pop song with tambourines. That’s the kind of music we do.”

True, but the focus on “Desire Lines” isn’t merely about mood and melody, which you could say has been the case on other albums. Campbell says its probably the first Camera Obscura record where you can tune out the vocals or lyrics and find something interesting that’ll catch your ear.

“Tucker got everybody a platform on this record,” she says. “Everybody gets a chance to show what they can do. There’s a lot of wonderful instrumentation on the record.”

You also hear a lot of restraint in songs like “I Missed Your Party,” whose shuffling beat languorously circles Campbell’s voice before subtly adding delicate touches of horns. “Cri Du Coeur” has a similarly slack vibe, like a prom song in slow motion. For Campbell, the new direction allowed her to think of the songwriting process differently.

“I was less concerned with arrangements than maybe I would have been in the past. Previously I’ve thought, ‘Maybe we’ll have strings here,’ ” she says. “I was a bit freer this time, less keen to dictate what should happen. The songs were less uptight, and I was willing to leave gaps and see what was going to happen. Some of the lyrics weren’t finished but got finished in the studio. We just let this album be its own thing.”